The last few years have seen rapid advancements in flash technology including planar 1x nm NAND, TLC, and 3D V-NAND. External high-speed interfaces such as USB 3.x have also become ubiquitous. The advent of Type-C has also enabled device vendors to agree upon a standardized connector for their equipment (be it mobile devices or desktop PCs). These advances have led to the appearance of compact bus-powered direct attached storage units with very high performance for day-to-day data transfer applications.

Introduction and Usage Impressions

SanDisk launched the Extreme 900 SSD at Computex 2015. The claim to fame was the availability of almost 2TB of flash in a bus-powered enclosure with a USB 3.1 Gen 2 Type-C interface. It was one of the first 2TB-class external drives to arrive in the market. Though the Samsung Portable SSD T3 beat it to our review bench, we finally got SanDisk's review sample last month.

Compared to the Samsung Portable SSD T3 (a palm-sized unit), the Extreme 900 is much bigger - similar to that of a slim 2.5" external hard drive. The unit comes in at approximately 18 x 83 x 133 mm and weighs 210g. It has a Type-C interface, but, the package comes with both Type-C to Type-C and Type-C to Type-A cables. This ensures that the drive is compatible with a wide variety of systems currently in the market.

SanDisk's Ultra II SSD has already been reviewed in detail before. The 1.92TB Extreme 900 uses two of the Ultra II 960GB SSDs. These SSDs use the Marvell 88SS9189 controller with SanDisk's 2nd Gen. 128Gbit 19nm TLC NAND. We will not go any deeper into the internal details of the Ultra II, but, one should note that it uses SanDisk's nCache 2.0 technology, where each die has a fixed number of blocks running in SLC mode. The 960GB Ultra II has 40GB of SLC cache, which translates to 80GB of SLC cache for the 1.92TB Extreme 900 as a whole.

In the rest of the review, we take a look at our testbed setup and evaluation methodology followed by our DAS benchmark numbers. In the final section, we take a look at the performance consistency and power consumption numbers.

Both SanDisk and Samsung have smaller capacity, lower priced versions of their drives that would be of interest. For example on Amazon SanDisk has a 960GB version for $500 which sounds like just 1 960 GB instead of two in RAID 0 (which may also solve the issue of no trim if its a single drive rather than RAID 0???). Samsung has: 250 GB T3 for $129, 500 for $197 and 1 TB for $427. The 500 GB actually seems pretty reasonable to me as its big enough to fit several VM's of the size I'd use it for and the price is still relatively low.Reply

External storage for a virtual machines seems like a good use case for the Extreme 900. I can't think of too many others that would justify the fairly steep MSRP vs storage capacity that can readily benefit from the added performance.Reply